1903.] 



Benzene in Poisoning hy Coal Gas. 



83 



other hand, the increased irritability of the muscles themselves is 

 the chief factor in the spinal reflex hyper-excitability. In coal gas 

 poison, when the lower centres are also paralysed by asphyxia, the 

 reflex excitability disappears. 



It is thus possible to refer the difference between intoxication by 

 coal gas and that by CO entirely to the influence of benzene, which 

 determines in its first stage vigorous excitatory motor phenomena. 

 In warm-blooded animals the conditions are quite different. Lorraine 

 Smith* found that an addition of 0*65 per cent, of benzene to air had 

 no effects on a guinea-pig, and Santessonf did not succeed in producing 

 either acute or chronic poisonous effects by administering benzene to 

 a rabbit by inhalation. In man, too, cases of poisoning by benzene 

 are few and far between. It is possible that the minute quantities, 

 which are absorbed by the lungs, are rapidly oxidised and excreted as 

 an aromatic sulphate. At any rate, in man, benzene plays no part 

 in the poisonous effects of coal gas. 



Summary of Results. 



(1) Coal gas produces first excitation and then rigor of the isolated 

 frog's muscle. 



(2) Frogs exposed to coal gas show excitatory phenomena which 

 are absent when the animal is placed in an atmosphere of CO or 

 nitrogen. 



(3) The specific effects of coal gas on frogs are determined by the 

 presence of benzene in the gas, and can be produced by air containing 

 the same percentage of benzene. 



(4) There is no reason to suppose that the poisonous effect of coal 

 gas on mammals is determined by anything except its content in CO. 



* Lorrain Smith, " The Poisonous Action of Coal- Gas and Carburetted Water- 

 Gas." ' Keport of the "Water-Gas Committee,' presented to both Houses of Parlia- 

 ment by command of Her Majesty, 1899, Appendix VII, p. 127. 



t Santesson, " (Jeber chronische Vergiftungen mit Steinkohlenbenzin," ' Archiv 

 fur Hygiene,' 31, p. 336. 



